The phase 2 study (NCT03441061), which was launched on Feb. 15, will include up to 40 adult patients with B-cell ALL who are in complete remission with molecular failure or molecular relapse at any point after 3 months of frontline therapy. The study is looking first at relapse-free survival, and secondarily at overall survival and minimal residual disease negativity rate overall and after the first cycle. In addition, the researchers will consider the safety of the drug in this setting.

Patients will be excluded from the study if they have Philadelphia chromosome–positive ALL, have active and uncontrolled disease or infection, have had a prior allogeneic stem cell transplant, or had radiotherapy or cancer chemotherapy or any investigational drug within 2 weeks of study entry.

Inotuzumab ozogamicin (Besponsa) was approved by the Food and Drug Administration in August 2017 for the treatment of adults with relapsed or refractory B-cell precursor ALL.

During the open-label, single-arm study, patients can receive up to six cycles of the drug and each cycle is 28 (plus or minus 7) days. Eligible patients will receive inotuzumab ozogamicin on days 1,8, and 15 of cycle 1 and days 1 and 8 of cycles 2-6.

If a patient chooses to undergo a stem cell transplant from a donor, that patient will receive only two to three cycles of the drug. Study participants may also be taken off treatment after cycle 2 if the disease has had no response.

The study is being conducted at MD Anderson Cancer Center and is expected to be completed in February 2023. The study is sponsored by Pfizer.